JP2866136B2 - Apparatus and method for controlling the concentration of a substance to be pumped - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an apparatus and a method for controlling the concentration of a substance to be pumped (pumped), and more particularly to a method for substantially controlling the concentration of a substance to be pumped. The present invention relates to a control device and a method for maintaining a constant.

As used herein, the term "concentration" refers to the degree of rigidity or resistance to movement or separation of constituent particles of the material being pumped, and includes "viscosity" and is somewhat broader than this viscosity. Has the meaning of The term "substance to be pumped" as used in the present invention includes a fluid containing a liquid or a solid mixture, or a fluid in a suspended state or a suspended state (hence, including a slurry or a colloid). It is not limited to fluids only.

[Conventional technology]

Controlling the concentration of the material being pumped is of considerable importance in various processing operations, for example, in the manufacture of cases where large water-soluble glue solids are periodically poured into glue tanks and dissolved in water. It is especially important for the gluing work in such as. If the ratio of water to glue cannot be precisely controlled or if the evaporation loss from the open glue tank is large, the concentration of glue in the liquid will change rapidly. Such evaporation losses occur especially when the liquid glue circulates from the application roll back to the glue supply reservoir. For example, about 14
In normal operation, maintained at 0 ° F (about 60 ° C), the evaporation rate of the solvent at normal room temperature is typically such that thinner must be replenished approximately every 30 minutes . If the concentration of the glue changes, the glue will be applied too much or too little to be applied by the applicator, or the pump will become clogged and the operation must be interrupted until the proper flow of the glue is restored. Must.

Various devices have been developed for controlling the concentration of the pumped fluid. For example, U.S. Pat.
This specification discloses a technique for controlling the flow of "stuff" (i.e., pulp and paper slurry) sent through a tube to a reservoir, wherein the overflow from the reservoir is accommodated in a pivoting tank. I have. If the viscosity of the pulp is too high, the pulp will accumulate in the pivot tank, and as the weight of the pulp in the pivot tank increases, a valve will operate to replenish the dilution water into the slurry tank. .

U.S. Pat. No. 1,669,412 discloses an apparatus for controlling pulp concentration using a pair of conical floats mounted upstream and downstream of a dilution water entry point into a pulp stream. The liquid slurry to the apparatus is controlled by different reactions of the two floats respectively responding to the high and low concentration streams.

U.S. Pat. No. 2,773,507 discloses a technique for measuring a torque proportional to the traction due to viscosity on a rotatable element and using the measured torque to control the flow of thinner.

U.S. Pat. No. 3,493,345 discloses a technique for controlling the viscosity of a polymer being pumped and determining the flow of an additive in response to an electrical signal that is a function of the power used in the pump.

[Problems to be solved by the invention]

While the prior art described above achieves fluid control, these controls are significantly inaccurate and require extremely complex instruments.

U.S. Pat. No. 1,881,200 discloses a technique for controlling the concentration by adjusting the temperature, and an improved version of the technique with an auxiliary heater is disclosed in U.S. Pat. No. 2,042,860. However, these temperature control devices require that the substance whose concentration is to be controlled must pass continuously through a plurality of environments at different process (processing) temperatures, or that the viscosity of the pumped substance depends on the temperature. If it doesn't change much, it's useless.

Therefore, by controlling the introduction of the concentration altering substance into the substance being pumped, the concentration of the substance, such as glue, being pumped to another processing unit, is simple but extremely reliable. It would be desirable to provide an apparatus and method.

Accordingly, the present invention provides a method comprising several steps, wherein one or more steps are related to each other, and an apparatus utilizing a configuration, a combination of elements and an arrangement of parts suitable for performing these steps. With the goal.

[Means for solving the problem]

In order to achieve the above and other objects, the present invention provides a method for controlling the concentration of a pumped substance by introducing a concentration-modifying substance such as a thinner, a thickener, and a solvent (herein, referred to as a "altering agent"). An apparatus and method are provided. The device of the invention comprises pump means, preferably a positive displacement pump, preferably in the form of a diaphragm pump, for pumping a substance at a predetermined flow rate from a reservoir by applying a predetermined level of force, and means for driving the pump. Have. Means for sensing the change in force applied to the pumped substance by the drive pump to move the substance, valve means for controlling the introduction of the denaturing agent into the substance, and the change in force required to pump the substance There is also provided means for controlling the operation of the valve means in response to the sensing of.

〔Example〕

The accompanying drawings show an apparatus for implementing the method of the invention,
The device has pump means consisting of a positive displacement pump, preferably a diaphragm pump 20. As is well known, diaphragm pumps generally include an elastic diaphragm (not shown), a suction valve 21 connected to a suction pipe 22, and a discharge valve 23 connected to a discharge pipe 24. The suction pipe 22 is the substance to be pumped located in the supply reservoir 26
Leads to 25. Reciprocating piston pump, gear pump,
Of course, other types of positive displacement pumps such as lobe pumps may be used.

The pump means according to the invention also comprises a drive means for driving the pump 2, which comprises a motor 28 connected to the diaphragm of the pump 20 via a connecting rod such as a piston rod 29 for reciprocating the diaphragm. . In the preferred embodiment, motor 28 is a known double-acting pneumatic cylinder, and a piston (not shown) in the motor is reciprocated by changing the air pressure on either side.
Of course, the piston rod 29 is connected to the piston.

The compressed gas source (not shown) is a manually operable ball valve
A regulator 31 is connected to the main supply line 30 via 31 and controls the pressure of the compressed gas transmitted through the line 30. The pressure controlled in this way controls the driving speed of the pump and thus the volume of fluid passing through the pump. If necessary, a pressure gauge 34 may be arranged in the line 30.

The apparatus of the present invention further comprises means, such as a pneumatic valve 36, for reciprocating the motor 28 and thus driving the pump 20. Valve 36 is preferably a known pilot-operated two-position four-way valve having a pair of outlet ports 38, 40 and an inlet port 41 connected to line 30 for supplying compressed gas to valve 36; It has a discharge port 39, preferably with a muffler, and a conventional internal movable flow direction control (not shown). valve
Since the flow directional control in 36 is actuated by air,
First control air inlet line 42 and second control air inlet line
43 is provided to provide a gas flow for steering the flow direction control element and to aspirate feed gas from corresponding pilot valves 44, 45 connected to line 30 via lines 46, 47, respectively. In the example shown, the pilot valve is
And the mechanical valve actuators 50, 51 are positioned so as to face each other along the same axis. The arm 52 mounted on the rod 29 can move with the rod 29 between two end positions, in which the arm contacts one of the actuators 50, 51 to actuate the pilot valve. The pilot valves 44, 45 are typically
Unless the valve is opened by contact with the actuators 50 and 51,
Spring biased to be maintained in the closed position. Alternatively, valve 36 may be actuated mechanically or electrically, in which case arm 52 serves to actuate a mechanical link or the necessary electrical contacts.

If the concentration of the substance being pumped changes, for example, the resistance to pumping will increase or decrease, but in order to maintain the same amount of pumping for that substance, the force applied to the pump must also be varied according to the concentration change. What must be done is obvious to a person skilled in the art.
Of course, the force applied to the pump also acts on the motor. Therefore, it is important to provide a means for sensing the occurrence of a change in the force applied to the pump. The sensing means includes pneumatic flow control valves 54, 56 located in lines connecting ports 38, 40 of valve 36 and each end of the cylinder of motor 28, respectively, wherein each control valve 54, 56 It acts to establish a pressure difference between the corresponding side (upper and lower) of the piston in the cylinder and the corresponding outlet port (38, 40) of the air valve 36. The means for sensing the occurrence of a change in force is conveniently
It can be constituted by a mounting part of the motor 28 and is in the form of a mechanical link mechanism allowing a restricted movement of the mounted motor 28 with respect to the frame 48. For this purpose, the link mechanism comprises a locking arm 58 fixed to the motor 28, this arm 58 being e.g.
The first ends of the links 60, 61 are pivotally connected, and the second ends of the links 60, 61 are pivotally connected to the frame 48. Link 60, 61, arm
58, motor 28 and frame 48 are arranged and arranged to support motor 28 such that it can move a limited amount away from pump 20 substantially along the longitudinal axis of rod 29, for example. One end of the arm 58 connects the motor 28 to the upper portion of the frame 48 via a compression spring 62 which normally biases toward the pump 20. The biasing force of the spring 62 can be adjusted by manually operating the adjusting screw (rod) 64. Alternatively, it should be understood that any other means of mounting the motor 28 while permitting similar relative movement with respect to the pump 20 can be used. For example, the motor 28 is fixed to a pair of sliders sliding on rails provided on the frame,
The slider may be spring biased toward the pump.

The other end of the arm 58 is provided with a finger 66 that projects substantially perpendicular to the movement path of the motor 28. A dilution valve 68 is attached to the frame 48, and its actuator button 67 is
The motor 28 is disposed in the finger movement path so as to contact the finger 66 when the motor 28 moves a predetermined distance away from the pump 20. A valve 68 is connected to control the flow of the modifying agent (eg, water) between the inlet line 70 and the outlet line 72, and the outlet line 72 communicates with the reservoir 26. When the motor 28 is in the non-moving position, the finger 66 abuts the stop block 69, preventing movement of the links 60, 61, arm 58 and motor 28 toward the pump 20.

In operation, gas, such as air, introduced into line 30 through valve 31 and regulator 32 is supplied by valve 36 to either port 38 or 40. Line 30 to port 38 or 40
The pressure of the air supplied to (eg, 60 pounds or about 27k
g) is controlled by the control valve 54 or 56, for example, 30 pounds (about 13.6k
The pressure is reduced to g). The reduced pressure is supplied to one side of the piston in the motor 28, and the arm 52 is connected to the pilot valve 44.
The piston moves in one direction until it contacts the actuator 50 or 51 of
The flow of air inside the motor 28 reverses and reverses the direction of motion of the piston in the motor 28. As is well known, as the piston reciprocates in the motor 28, the diaphragm in the pump 20 flexes substantially perpendicular to its plane, and when flexed in one direction,
When a substance 25 (hereinafter, referred to as “glue”) from the reservoir 26 is sucked into the internal chamber of the pump 20 via the suction valve 21 and deflects in the opposite direction, the glue is discharged from the internal chamber of the pump to the discharge valve 23. Through the outlet pipe 24. This operation of the pneumatic cylinder motor 28, diaphragm pump 20, and pilot operated two position four way valve 36 is well known in the art.

For a constant concentration of glue and for a given pressure differential normally provided by valves 54, 56, the compression force of spring 62 causes motor 28 to maintain a substantially constant position with respect to frame 48 during pumping. Can be set to Spring
This is because the force acting on 62 is the same as the force acting for pumping the glue and acts in the opposite direction.

As described above, even when the concentration of the glue changes, the force applied to the glue must also be changed in accordance with the change in the concentration in order to maintain a constant amount of the substance to be pumped. Therefore, for example, when the density of the glue increases, the resistance of the glue at the time of pumping also increases. When the resistance of the glue increases, the operating speed of the motor 28 decreases,
The pressure of the air fluid in the cylinder at the motor 28 increases to approach the output value of 60 pounds provided at the outlet port of the valve 36. Thus, the pressure differential provided by valves 54, 56 is small. When the pressure in the cylinder of the motor 28 increases, it not only presses the piston of the motor to drive the glue with the increased resistance, but also inhibits the preset equilibrium between the spring force and the pumping force. As a result, the motor is driven away from the pump 20 until the spring 62 is compressed enough to rebalance these forces. When the motor 28 moves against the biasing force of the spring 62, the fingers 66 contact the actuator button 67 of the valve 68 to open the valve 68 and introduce the altering agent (in this case, water) into the substance 25. Preferably, a known mixing device is provided in the reservoir, and when the altering agent is introduced, the altering agent is immediately mixed with the substance 25 in the reservoir 26 to keep the substance 25 at a substantially uniform concentration. .

Of course, low concentration glue pump from reservoir 26
When sucked into 20, the speed of motor 28 increases because resistance to pumping is reduced. For this reason, the passage time of the gas passing through the valves 54 and 56 is shortened, and the valves 54 and 56
The pressure differential provided by 56 increases and the spring and pumping forces become unbalanced. As a result, motor 28 is driven toward pump 20 until the compression of spring 62 is reduced enough to rebalance these forces. Spring
This movement of motor 28 due to the biasing force of 62
The contact between 66 and the actuator button 67 of the valve 68 is cut off,
Valve 68 closes to prevent the introduction of the altering agent into reservoir 26.

Since various modifications can be made without departing from the spirit of the present invention, the embodiment described and illustrated above is merely an example, and the present invention is not limited to this embodiment.

[Brief description of the drawings]

The accompanying drawings are schematic partial cross-sectional views of an apparatus for performing the method of the present invention. [Explanation of Signs of Main Parts] 20 ... Pump, 25 ... Material 26 ... Reservoir, 28 ... Motor 29 ... Piston rod, 36 ... Air valve 44, 45 ... Pilot valve 48 ... Frame, 54 , 56… Flow control valve 58… Locking arm, 62… Spring 66… Finger 67… Actuator button 68… Dilution valve

Claims (5)

(57) [Claims] 1. A substance (25) pumped from a reservoir (26) by introducing a denaturing agent into the substance (25).
A device (20) for controlling the concentration of said substance (25), said pump (20) for pumping said substance (25) from said reservoir (26);
Motor means (28) coupled to drive the pump (20); and the pump (20) drives the substance (20) when the pump (20) is driven to pump the substance from the reservoir. 25. A substance concentration control device comprising: sensing means for sensing a change in a force applied to the substance (25); and control valve means (68) for controlling introduction of the altering agent into the substance (25). The means include a mechanically resilient mounter (58, 60, 61, 62) of the motor means (28) allowing relative movement of the motor means (28) toward and away from the pump (20). Thereby, when the concentration of the substance (25) is in a steady state, between the force acting to cause the relative movement and the force applied to the motor means (28) by the resilient mounter. Changes in the concentration of the substance (25) so as to cause a change in the relative movement. There is a substantial equilibrium that tends to be inhibited by the control valve means (68) to control the introduction of the denaturant into the substance (25). Control apparatus in response to a change in relative movement caused by a corresponding change in the concentration of a substance. 2. The substance concentration control device according to claim 1, wherein said pump (20) is a positive displacement pump. 3. The motor means (28) includes a cylinder having a surface portion capable of reciprocating movement, an air source having a predetermined pressure, and an air source connected to the air source and the cylinder for reciprocating the reciprocating surface portion. Air valve means (36,44,45) for alternately supplying air to both sides of said reciprocable surface for movement.
Means (29) connected to said reciprocable surface for driving said pump (20). 4. A motor according to claim 1, wherein said motor means comprises a double-acting pneumatic cylinder motor.
2. The substance concentration control device according to 1. 5. The air valve means (36, 44, 4)
5) and the motor means (28) connected between the air supplied to drive the motor means (28) and the motor means (28) during steady state operation of the pump (20). ), And a pressure reducing valve (54, 56) for providing a pressure difference with the air in the material (2, 3).
The motor means (28) responds to the change in the pressure difference due to the change in the concentration of the mechanical elastic mounter (58, 60, 61, 6).
The substance concentration control apparatus according to claim 4, wherein the substance concentration control apparatus moves in 2).